The invention resides in the field of building construction using mortise and tenon joints to connect separate structural members, one to the other. More particularly, the invention concerns a mortise and tenon joint between structural members which is self-locking.
Mortise and tenon joints have been used to join separate members of structures, such as beams, joists and/or supports therefor, since the first use of permanent wooden structures for support of a covering used for dwelling and shelter. The early mortise and tenon joints have been modified and changed over the years to adapt to the current needs of the society then using such building techniques. Although wooden structures are no longer the primary type of dwelling used in today's society, the practice of joining wooden structural members using mortise and tenon joints continues incorporating present day technology.
It has long been the practice to shape a particular mortise to mate exactly with the tenon to be placed therein at the time of making the joint. This practice allowed for different angles of attachment of one structural member to the other in accordance with the specific requirements of that type of structure. This practice entailed shaving the tenon, beveling either a shoulder on the mortice or chamfering the tenon, or similar adjustment to fit the tenon into the mortise at the desired angle. Once fitted exactly, the joint was secured by fastening one structural member to the other using bolts, nails, wedges or other wooden or metal fasteners.
Present day construction practices require simplified methods of completing structures due to the lack of training in crafts, such as joining, by those building wooden structures. This group includes the handyman and homeowner in addition to the carpenter and other tradesmen.
The homeowner of today has become increasingly conscious of allocating space within the dwelling to view and enjoy the environment. In order to accommodate this new requirement sun spaces, greenhouses and the like are being added to existing homes and planned as part of new residential construction. In either case, the sun space or greenhouse is effectively added onto the basic structure using a metal or wooden beam system with similar type supports. The sun space or greenhouse structure usually has wall elements standing perpendicular to the ground with a roof at an angle or pitch to mate with the support structure of the building and to take advantage of the sun's rays for warming.
The problem for the manufacturer and builder has become the angle or pitch of the roof beams of the sun space or greenhouse when connected to the building support structure. Each such space is unique in that the span from the wall element to the existing building header can vary which, in turn, will change the angle or pitch of the roof beams of the sun space or greenhouse. A change in angle or pitch of the roof beams will require a change or modification in the shape of the mortise or tenon. An adjustment must be made by shaving the tenon, beveling a shoulder of the mortise, or chamfering the tenon, among other methods of fitting the joint together properly. The skilled labor involved in making these kinds of changes and modifications is not usually available at the job site and, if it is, the labor is extremely costly.
The present invention obviates the need for changing and/or modifying the joint elements at the job site to properly fit the joint by implementing a self-locking mechanism within the mortise and tenon joint. The invention also permits the manufacturing of uniform structural elements to be fit together to make a proper joint at the job site with little need for adjustment. Any adjustments which may be necessary for a proper joint fit can be performed by the person building the structure without the need for a specially skilled craftsman.
It is, therefore, an object of the present invention to increase the structural integrity and strength at the attachment point or joint of the several structural elements of the sun space or greenhouse using a self-locking mortise and tenon joint.
It is a further object of the present invention to increase the safety and reduce the risk of damage to existing structures and injuries to persons during installation of sun spaces or greenhouses by using a self-locking mortise and tenon joint.
It is another object of the present invention to make the installation of the structural members easier by reducing the need for modifications at the job site for differing roof pitches.
It is still a further object of the present invention to provide greater economies in manufacturing by reducing the need to manufacture a number of mortise and tenon joints of varying angles between the two structural members allowing for inventorying of a lesser number of structural member types.
It is still another object of the present invention to shorten the required installation time for joining the several structural members comprising the sun space or greenhouse at the job site by incorporating the self-locking mortise and tenon joint into the several structural members.
Other objects will appear hereinafter.